The Nervous System

The Nervous System

Structure and Function of Nervous System

  • The nervous system is an intricate network of nerves and cells, known as neurons, that transmit signals between different parts of the body.
  • It is primarily composed of the central nervous system (CNS) and the peripheral nervous system (PNS).
  • The CNS includes the brain and spinal cord. It acts as the body’s control centre, processing information and sending instructions.
  • The PNS includes all nerves outside the CNS. It connects the CNS to limbs and organs.

Neurons and Transmission of Nerve Impulses

  • Neurons are highly specialised cells adapted to transmit electrical impulses from one part of the body to another.
  • Each neuron consists of a cell body, dendrites and an axon.
  • Dendrites receive stimuli and transmit the impulse to the cell body. The axon transfers the impulse away from the cell body.
  • The junction between two neurons is called a synapse. Chemicals known as neurotransmitters carry the impulse across the synapse.
  • Myelin sheath, a fatty layer, insulates the neuron and speeds up the transmission of nerve impulses by forcing them to jump from one node of Ranvier to the next.

The Brain and its Functions

  • The brain is responsible for coordinating most of our body’s activities. It’s divided into three main parts: the cerebrum, cerebellum, and medulla oblongata.
  • The cerebrum is the largest part of the brain and controls voluntary actions, intelligence, memory, and language.
  • The cerebellum controls balance and coordination.
  • The medulla oblongata controls automatic actions such as heart rate and breathing.

Role of Nervous System in Response to Stimuli

  • The nervous system provides a fast, short-term response to changes in the environment known as stimuli.
  • When a stimulus is detected by receptors, messages are sent as electrical impulses along neurons to the CNS.
  • The CNS interprets the information and sends messages along motor neurons to the effectors, causing them to respond.

By understanding the structure and function of the nervous system, you can have a comprehensive picture of how it helps the body to interact with the environment. It would be helpful if specific attention is given to neurons as they play a vital role in this system.